Recently, image data such as a photograph and personal information such as a telephone directory can be used in mobile devices, such as a mobile telephone. In the mobile devices, a display screen can often be customized by a user. For example, personal information, a favorite photograph, or a memo can be presented on a standby screen or a menu screen.
It is possible that information in a mobile device may be misappropriated by an unintended third party. For example, the unintended third party can see the standby screen presenting the personal information customized by the user.
Accordingly, there is a need for improved information security in the mobile devices.